Float



May 7, 1%@ E, R. ARMSTRONG FLOAT Filed Deo. fr, 1944 '7 Sheets-Sheet 2May E946.

E. R ARMSTRONG FLOAT 7 sheets-sheet 5 F'iled Deo. '7, 1944 n 555.- 24 +1,i I

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FLOAT Filed Deo. 7, 1944 7 Sheets-Sheet 5 May 7, 1946. E. R. ARMSTRONGFLOAT Filed Dec. 7, 1944 7 Sheets-Sheet 6 May 7, 1946. E, R. ARMSTRONG'FLOAT Filed Deo. '7, 1944 7 Sheets-Sheet 7 rig.

Patented` May 7, 1946` UNITED STATES FLOAT Edward R. Armstrong,Philadelphia, Pa. Application December 7, 1944, Serial No. 587,067

8 Claims.

This invention relates to floats and anchorage systems therefor, and hasas its main object to provide for iloat stabilization, regardless ofwind and wave conditions or changes in deck loading. While the inventionis not limited in its application, an important field of usefulness isin offshore drilling operations, and for this reason the embodiment tobe hereinafter described by way of example takes the form of an offshoredrilling In accordance with the invention the iloat comprisesessentially a platform structure or deck supported on a suitable numberof columnar buoyancy units. Such units are. 4in themselves, of greateffect in equalizing energy eiiects released by wave action, and thereasons for this are fully set forth in my prior Patent No. 1,892,125,granted December 27, 1932'. The anchoring means comprises a verticalsystem utilizing what I shall herein term weight anchors, since theyrely primarily on their weight for anchoring eiiect. During welldrilling` operations these anchors are bottomed and are so arranged asto enectively elim' inate roll and pitch of the iloat due to waterdisturbances, and consequently the working platform is maintainedentirely stable. Since the float should be mobile in order to be able toproceed to a new drilling location upon completion of a well,

. I provide means for the adjustment oi' buoyancy effects so that whilethe anchors are able to hold the float submerged below its normalilotation level during the building of a well, they are, nevertheless,liftable by the float to permit the vfree travel of the latter. Thistravel can be effected by the manipulation oi horizontal mooring cableswhich are provided.

.Without further general discussion, I shall describe the inventionasjembodied in the structures shown in the accompanying drawings, inwhich: i

Figure 1 is 'a plan view of a float and mooring means in accordance withthe invention.

Figure 2 is a side elevation of the structure shown in Figure l, aderrickbeing additionally shown.

Figure 3 is an elevation like that of Figure 2, but with parts in adiilerent relationship. i .f

Figure 4 is an end elevation of the structure as shown in Figure 3.

Figure 5 is a section substantially on line 5--5 of Figure 1.

Figure 5a is a plan view of an anchor.

Figure 6 is a fragmentary view on an enlarged scale showing inelevationreleasable guy anchorlng means which appear also in Figures 2and 3.

Figure 'l is a section substantially on line 1-1 ofFlgllre 6. 4,

Figure 8 is a fragmentary view on an enlarged scale showing in elevationa braclretl which appears also in Figures 2, 3 and 5. v

Figure 9 is a section substantially on line 9-9 of Figure 8. l

Figure 10 is a fragmentary View on the scale of Figure 8 showing invertical longitudinal sec-` tion a. releasable coupling which appearsalso in Figures 2 and 3. Figure 11 is a section substantially on linelI-II ofFigure 10.

Figure 12 is a'plan view of the structure oiFigure 1 on a smaller scaleand showing horizontal mooring means in operative disposition.

Figure 13 is a side elevation'oi the structure fas shown in Figure 12. 4

Figure 14 is an end elevation of the iloat and anchorage means on thescale of Figures 12 and i3, but showing a different arrangement ofhorizontal mooring means, and

Figure 15 is a plan view of the arrangement shown in Figure 14.

Referring to the drawings, reference numeral i generally designates afiat rectangular platform or deck structure here shown as. comprisingthree sections 2l, 22 and 23 rigidly connected together. The platformstructure comprises longitudinal truss members of which a side member isindicated at 2l, Figure 2, and transverse truss members, oi which an endmember is indicated at 25, Figure 4. As shown in Figure 1, the centersection 22 comprises longitudinal and transverse beams 28 and 21defining a central symmetricallydisposed square 2B which includesfurther transverse members 29. Provided at the center of the square is acircular opening 30 through which the well building operations can becarried-out. Reference numerals 3l and 32 designate opposed paralleichannel members secured to the top oi.' the platform in equally spacedrelation from the longitudinal central plane of the platform, thechannels receiving the wheels of a truck 33 on which is mounted aderrick 34 whose structure is open at the left, Figure 2. The lower endoi' the derrick is. angled to a transverse l pivot 3B supported on thetruck 33 and rests against and is normally secured to triangular framemembers 3B and -31 which are secured to the truck. Also mounted on thetruck is a draw works 38 controlling cables 39 and 40, of which theformer is led beneath a guide pulley 4I mounted on the derrick. andthence to a crown 55 block 42 and a travelling block 43. Cable 40 Vrunsto the top of the derrick, and when the derrick is unlocked from theframe members 35 and 31, it can swing to the left under the control ofcable 40, and the travelling block .can accordingly swing outwardly ofthe derrick as permitted by the open structure at the left. Thus, byrun-A, ning the truck 33 to the left-hand end of the rails Figure 2, thederrick can operate off of the left-hand end of the platform. In Figure2 the truck is locked to the rails with the travelling block directlyabove the opening 30.

Secured beneath the deck structure 2l are, as here shown, eight columnarbuoyancy units 44 to 5|, which may all be of the constructionparticularly shown in Figure 5. The buoyancy units are equally spacedlongitudinally of the platform, the transverse spacing is the same asthe longitudinal spacing, as here shown, and the unitsare symmetricallydisposed with respect to the platform.

Referring to Figure 5, the unit 41 comprises a vertical cylindricalmember 52 which extendsv through to the top of the platform and isrigidly secured thereto. A vertical cylindrical member 53 surroundsmember 52 concentrically there-` with and has its upper end rigidlyilxed to the bottom of the platform. Below member 53 a furthercylindrical member 54 surrounds member 52 `concentrically therewith,member 54 terminating downwardlyin a conical formation 55 which extendsin to member 52 just above the lower extremity thereof and is sealedthereto.

Member v53 is divided into a numberof water-'- tight compartmentsit byhorizontal annular partitions 56, and member 541s separatedintocompartments by sealed partitions 51 fand 58 providing compartments59, 50 and 8|, of which the latter is water-tight. Compartment B9-hasbottom openings as at 62, and compartment 69 has bottom openings asiat63,v these openings being just above the partitions 51|a`ndj58, vrespectively.' A pipe 64 extends from the toplof-compartment 59 to avalve 65, and thence to asouree ofcompressed air 86, the valve andsource disposed in the, deck structure. The top of compartment 60ylssimilarly connected by a pipe 61 with a valve 68'and source ofcompressed air 89. The valves 65 and 68 are ofthe fourway type, having ashut-oil position. a position in which the pipes 64 and 61 are open tothe 5o atmosphere, and a position in which the pipes are connectedto thecompressed air sources. In

the first position of the valves, with tanks 69 and f 60 empty, thetanks'will remain substantially so even though the -compartments aresubmerged.

-With the compartments submerged, the valves in lthe second-mentionedposition will permit floodthe respective compartments throughout.

. Adjacent sides of the 'lower enlargements, as' at 54, of the buoyancyunits have iixed thereto brackets 10 of the form particularly shown inFigures `8 and 9, these brackets being secured tc the `enlargements atthe same level, which is preferably that of the partitions as-at 51.Each and 'l2 pierced to receive bolts 13 and 14 and to receive a bolt 15on which is rotatable a pulley 18. 'I'he bolts 14 of opposed bracketsengage ttings, as at 18, in which are seized the lends of diagonal guysas at 19, which run upwardly and are anchored to the bottom of theplatform. This arrangement applies between all of the -buoyancy umts,except the units 41 and 49, where a special releasable bracing system isprovided for a Purpose which will later appear.v

Referring to Figures 2, 8 and 9, columns 41 and 49 are equipped withopposed brackets 10 and have pivoted to their bolts 14 strut parts 80and 8| having normally interengaged hooked ends 82 and 83, asparticularly shown in Figure l1. Reference numeral 84 designates asleeve which holds the ends in interengaged relation. By mov.. ing thesleeve to the right against a compression greturn spring 85, thejoint isuncovered and the 'parts 80 and V8| may be swung upwardly by pulling oncables 86 and 81, Figure 2, which run-to [the deck. The sleeve can bemoved to uncoupling vvrelation by pullingon a cable 88 which runs to thepulleys 18 .of the adjacent fitting 10, `and through a spacer98 which'is engaged by a yoke will be tautened, and the slide retained by meansof a pivoted dog |52, which can be releasedeby pulling on a control wire|03. 'I'he locking dog for'slide 9| is indicated by the referencenumeral |04, Figure 2.

Referring to Figure l, the four buoyancy col- -umns at the left areconnected by diagonal horizontally disposed ties |65 and |06, and thefour columns at the right are connected by similar ties |01 and |58.Such ties are omitted at the center section, and, instead, diagonallyarranged trusses |89 to ||2 are provided, these extending from thecolumns to the corners of the square structure 28 for 'the rigid suDpOrtof the center section against the weight of the derrick and otherequipment.

As here shown, weight anchors ||3vto |2l,are associated with thebuoyancy units, these anchors being all of the construction particularlyshown in Figures 5 and 5a. Referring to that iigure, the anchor I6comprises a frustoconical outer wall ||1 and an inverted frustoconicaltop wall ||8- providing a recess adapted to receive the lower conicalend of the buoyancy column 41 with clearance for the projectingextremity of member 52. Spacer stripsl I9' are cured to the top wall||8' in radial planes. A frusta-conical wall |28 is secured tothe loweredge of top wall ||8 and its'lower edge is connected with the outershell ||1 through an annular wall |2|', so that a buoyancy tank orcompartment |22 is provided. Wall |28 has secured thereto a reinforcedbottom wall |23, to which is centrally fixed an uprightmember |24bifurcated at its upper end and supporting a transverse pin |25. Wall|28' and bottom plate |23 detlne a compartment of the outer wall ||1 isinterlorly rimmed by a -relatively narrow annulus |21, the connectionbracket 18 comprises parallel vertical flanges 1| 75 being reinforced bygussets |28. Below wall |2| assauts elling block |32 by means of ahoisting cable |33, the travelling block having a hook |34 engaged.

with the pin |25. The upper end of cable |22 is led to a winch |35mounted in the platform structure and eifective to pay out or take inthe cable and to retain or lock the cable in any adjusted relation.

Reference numeral |30 designates a flexible hose connected at its lowerend to a pipe |31 whose open end is disposed at the top of compartment|22, the latter being provided with bottom openings |38 in wall |20'.The hose is led up through the passage or shaft defined by member` 52and over a pulley |30 to a drum |40 provided with a suitable drive forwinding, unwinding, and locking. The drum end of the hone is inconnection through a swivel coupling with a pipe |4| which' leadsthrough a valve |42 to a source of compressed air |43. Valve |42 is afourway valve, the same as valves 85 and 58.

Reference numeral |44 designates a guy connected to the upright |24 ofanchor IIB and running across to the pulleyl of the bracket on theadjacent side of column 45, and thence up.- wardly to a winch |45mounted in the platform. The spacer strips ||9 provide clearance for theguy |44 so that the anchor ||8 can be pulled into contact with thebottom oi the column without cooking. A similar guy |45 runs to thebracket 10 on column 41, and thence to a winch |41. Similar diagonalguys are provided between all of the buoyancy columns and anchors,except columns 41 and 49 and associated anchors. In Figure 4 the enddiagonal guys are designated |40' and |48'.

In Figure 2' the anchors are all shown as being held against the bottomsof th'e columns and all ballast compartments are assumed to be empty. Insuch case the structure is in condition to travel to the point of usewith the least possible draft, and the water line in this case will beat X. with a draft oi', say, 20 feet. The total height of the float andanchors in the relation shown in Figure 2 is 95 feet in the presentexample, and with this gure as a base, thc other proportions will beevident.

vAssuming uthat the water at the location to be drilled is not overabout 65 feet deep, when the structure is in position the buoyancy tanksoi the anchors and the lower buoyancy unit compartments or tanks can befilled with water, with the result th'at the anchors will be bottomed insupporting relation to the iloat. The relation oi parts will remain thesame as shown in Figure 2,

- units is such that when the tanks are illled with water, the totalbuoyancy eilect will oe over-balops after the anchors are bottomed.Therefore, with all buoyancy tanks fully ilooded and the anchor cables|38 tensioned, the iloat is ilrmly seated in a manner not to' beinfluenced by water disturbances.

In the situation lust discussed, the float rests on the anchors with theweight which is in excess of the total buoyancy effect of the buoyancyunits.

- However, the ballast tanks of the buoyancy units may be blown out torestore the residual buoyancy in whole or in part, and, in that case,the anchors alone will serve as the hold down means. When it is desiredto move the iloat, it is only necessary to blow out the anchors throughthe openings |30 which, it will be noted, are directed beneath thebottom plate |23. The issuing water serves to break the clinging effect.When the anchor tanks are fully blown out, each anchor, as contemplatedin the present example, h'as a buoyancy effect of 50 tons'whichsupplements the buoyancy effect of the buoyancy units.

It will be evident that with the described relationship, it would beimpossible for the float to lift the full weight of the anchors, whichis 2000 tons as against the 1600 to 1300 tons maximum residual buoyancyof th'e float. However, by blowing out the tanks to a suitable extentthey can bereadily lifted, and by blowing them out completely they add aconsiderable buoyancy effect of their own, as above-mentioned.

Where the water is deeper, as contemplated in Figures 3 and 4, whenthelocation is reached the anchors may be iiooded and lowered to thebottom, and then the Winches operated to pull the iioat down so that thebottom of the platform is, say, 30 feet above the water level. Since thev anchor tackles are individually operable the platanced. Each anchorhas a weight oi' 250 tons,

submerged, and, consequently, there is a total anchoring weight of 2000tons which is considerably enhanced by the clinging eiect whichdevelform can be pulled to an exactly level service draft or condition,regardless of bottom irregularities. With the ballast tanks of thebuoyancy i units empty, there may be an upward pull as high as 250 tonsper anchor and such a. tension eiect will maintain the float against anyrolling and pitching, regardless of wave conditions. As the anchors arelowered the guys as at |44 and |46 are also paid out yand then tautenedso that the buoyancy units are maintained directly above theirassociated anchor units. 4 the depth is assumed to be 165 feet and up tothis depth the guys have a good stabilizing eiect. When greatly belowthis depth it is preferable to use the horizontal mooring cables whosearrangement will be later described.

In reaching a setting such as is shown in Figures 3 and ,4 it is moreeconomical to iiood th'e ballast tanks of the buoyancy units along withthe' ballast tanks .of the anchors, decreasing the re- 1 s ballast tanksempty.

As another possibility. the same residual iloat buoyancy of 1600 to 1800tons may be assumed, but assume that the anchors are partly blown out sothat each has an effective submerged weight of tons for an aggregate of1000 tons. Under these circumstances the anchors would obviously notsumce, at least by weight alone, to

In. Figures 3 and hold the buoyancy units submerged below their normalnotation level. However. under the as-l can be lifted without beingblown at all, and, inthis case it would be the same as though anchors,

of fixed effects were'used.

In Figures 12 and 13 the float is shown as anchored in 300 feet of waterand positioned by means of horizontal mooring cables |48 to |51 whichextend from Winches at the corners of the float (see Figure 2) down tosheaves at. the top of the corner column enlargements and thence toanchors about 1200 feet away from the float, the cables lying in planeswhich substantially bisect the corner angles of the float, as hereshown. In Figure 3 a well casing |52 is shown as lprojecting above thewater to within a short distance of the platform. Assuming the well tohave been completed and that the float is to be moved, the anchors arehauled up and the structure will rise but strut portions 80 and 8|, atleast, will still be below the top of the casing. The strut portions aredisconnected and swung upwardly and,

. if necessary, slides 9| and 92 are released and pulled together sothat guys l! and 90 are slackened and can be picked up by a hook andlifted above the height of the casing. Then by manipulating thehorizontal mooring cables the float can be moved laterally away fro'mthe casing which is cleared by reason of the release of the strutmembers 80 and 8| and thev` cables 89 and 80. these being thereuponreturned to operative relation. The horizontal cables maythen be used tomove the Vrig to a new location, the anchors being re-set as required. li

In Figures 14 and 15 a more'compiete horizontal mooring system is shownin that eight f cables |60 to |81 are provided, two extending from eachcorner at right angles to an end and side of the float respectively. Thedisposition is f shown for depths of one hundred, two hundred, e Landthree hundred feet. At the one hundred foot depth the cables areanchored -three hundred feet away from the'float and six hundred feetaway 'Aat the two hundred foot depth. At these depths 1 the cables canbe supplemented by the guys as at |44' and |46' or the cables alone ortheguys alone may be used. At the three hundred feet depth the cablesare shown as anchored a thousand feet away from the float and the guysare omitted since at this depth they would be too steep for an adequateeffect. Where the mooring cables are of such length that their weightwould cause them to sag substantially I provide them with readily nattachable and detachable buoys |88 so that they are maintainedsubstantially straight, as shown. Each cable runs to a separate winch onthe float and the buoys are attached as the cables are paid out andremoved as the cables 'are'takenin AWhile I have-shown an anchorassociated with veach buoyancy unit it should be understood that thisneed not necessarily be always the case.

When the following claims mention submerging the buoyancy units belowtheir normal flotation the vresidual buoyancy of the float as-determinedby the condition of the float ballast tanks. I do not limit myself tothe form and arrangement of parts herein specifically disclosed exceptas in the claims. 4

I claim:4

1. In combination, a float comprising a platform structure, verticalcolumnar buoyancy units beneath said platform structure for the .supportof the same, weight anchors beneath said platform structure, verticallyextending cables in connection with said anchors respectively.` Winchescarried by said platform structure in connection with said cables forthe independent con.. trol thereof including the locking thereof in anyadjusted relation, each of said anchors including a buoyancy tank, andmeans for controllabilil flooding and emptying said tanks whereby saidanchors can be adjusted so that when bottomed they are capable ofholding said buoyancy umts submerged below the normal flotation levelthereof orso that they areliftable by the buoyancy elect of saidbuoyancy units to permit movement of the float to another location, theheight of the buoyancy units and the horizontal distribution of thebuoyancy units and anchors being such and thehold-down capacity of theanchors being such as to enable the buoyancy units to be held 'so farbelow their normal flotation level and with such tension on the cablesas to render the anchored float maintainable against rolling andpitching regardless of wave conditions with the Ibottom of the platformabove the tops of the waves.

2. In combination, a float comprising a platform structure, hollowvertical columnar buoyancy units beneath said platform structure for thesupport of the same, weight anchors beneath said platform structure.vertically extending cables in connection with said anchorsrespectively, Winches carried by said platform structure in connectionwith said cables for the independent control thereof including thelocking thereof in any adjusted relation, and means for controllablyflooding and emptying said buoyancy units, said anchors being capablevwhen bottomed and said buoyancy units suitably flooded of holding saidbuoyancy units submerged below their normal notation level and beingliftable by said buoyancy unit/s when the latter vare suitably emptiedto permit movement of the float to another location.' the height of thebuoyancy units and the horizontal distribution of the buoyancy units andanchors being such and the hold-down capacity of the anchors being suchas to enable the buoyancy units to be held so far below their normalflotation level and with such tension on the cables as to render theanchored float maintainable against rolling and pitching regardless ofwave conditions with the bottom of the platform above the tops of. the

waves.

3. In combination, a float comprising a piatform structure, hollowvertical columnar buoyancy units beneath said platform structure for thesupport of the same, means for controllably flooding and emptying saidbuoyancy units for the control of their buoyancy effect, weight anchorsbeneath said platform structure, vertically extending cables inconnection with said anchors respectively. Winches carried by saidplatform structure in connection with said cables for the level, thelevel referred to is that established by they and the buoyancy unitssuitably flooded of f holding said buoyancy units submerged below'assauts their normal notation level, and when they and the buoyancyunits are suitably emptied being liftable by said buoyancy units topermit movement of the float to another location, the height of thebuoyancy units and the horizontal distribution of the buoyancy units andanchors being such and the hold-down capacity of the anchors 'being suchas to enable the buoyancy units to be lueld so far below their normalflotation level and with such tension on the cables as to tender theanchored oat maintainable against rolling and pitching regardless ofwave conditions with the bottom of the platform above the tops of thewaves.

4. In combination, a float comprising a platform structure, verticalcolumnar buoyancy units beneath said platform structure for the supportof the same, each of said buoyancy units having a. vertical passagetherethrough, weight anchors beneath said buoyancy units respectively,cables in connection with said anchors and disposed in said passages,Winches carried by said platform structure in connection with saidcables for the independent control thereof including the locking thereofin any adjusted relation, each of said anchois including a buoyancytank, and means for controllably ilooding and emptying said tanks, saidanchors being capable when bottomed and their tanks suitably flooded ofholding said buoyancy units submerged below their normal flotation leveland when their tanks are suitably emptied being liftable by saidbuoyancy umts to permit movement of the float to another location, theheight of the buoyancy units and the horizontal distribution of thebuoyancy unitsand anchors being such and the hold-down capacity of theanchors being such as to enable the buoyancy units to be held so farbelow their normal notation level and with such tension on the cables asto render the' anchored float maintainable against rolling and pitchingregardless of chors and disposed in said passages, Winches ear-` ried bysaid platform structure in connection with said cables for theindependent control thereof including the locking thereof in anyadjusted relation, said anchors being capable when bottomed and saidbuoyancy units suitablyfloored of holding said buoyancy units submergedbelow their normal flotation level and being liftable by said buoyancyumts when the latter are suitably emptied to permit movement of thefloat to anand the horizontal distribution of the buoyancy units andanchors being such and the hold-down capacity of the anchors being suchas to enable the buoyancy units to be held so far below their normalflotation level and with such tension on the cables as to render theanchored float maintainable against rolling and pitching regardless ofwave conditions with the bottom of the platform above the tops of thewaves.

6. In combination, a float comprising a platform structure, verticalcolumnar buoyancy units beneath said platform structure for the supportof the same, means for controllably flooding and emptying said buoyancyunits for the control of their buoyancy effect, each of said buoyancyunits having a vertical passage therethrough, weight anchors beneathsaid buoyancy units respectively, cables in connection with said anchorsand disposed in said passages, Winches carried by said platformstructure in connection with said cables for the independent controlthereof including the locking thereof in any adjusted relation, each ofsaid anchors including a buoyancy tank, and means for controllably-ooding and emptying said tanks, said anchors being capable whenbottomed and they and the buoyancy units suitably flooded of holdingsaid buoyancy units submerged below their normal flotation level, andwhen they and they buoyancy units are suitably emptied being liftable bysaid buoyancy units to permit movement of the float to another location,the height of the buoyancy units and the horizontal distribution of thebuoyancy units and anchors other location, the height of the buoyancyunits 1 being such and the holdfdown capacity of the anchors being suchas to enable the buoyancy units to be held so far below their normalflotation level and with such tension on the cables as to render theanchored float maintainable against rolling and pitching regardless ofwave conditions with the bottom of the platform` above the tops of thewaves.

7. A float of the type described comprising a deck, a supportingstructure therefor, a plurality of buoyancy units secured in spacedrelation in and forming a part of the supporting structure, saidbuoyancy units in the aggregate giving the float substantial residualbuoyancy when riding at service draft, some at least of said buoyancyunits having a central shaft open at the bot--V tom, and hoisting meansin said shaftsadapted to be connected to anchorage means.

8. A float of the type described comprising a deck, a supportingstructure therefor, a plurality of buoyancy units secured in spacedrelation in and forming. a part of the supporting structure. saidbuoyancy umts in the aggregate giving the float substantial residualbuoyancy when riding means. Y 4

EDWARD R. ARMSTRONG.

